自发性高血压大鼠血管α1肾上腺素受体亚型的改变

本工作在离体与整体条件下比较易卒中型自发性高血压(SHRSP)大鼠与WKY大鼠血管中α_1受体的两种亚型。在离体灌流的主动脉、肾动脉与肠系膜动脉,50μmol/L氯甲基可乐定(CEC)预温育30min可使α_1受体激动时引起的最大收缩张力在SHRSP与WKY大鼠分别降为对照时的31.4±8.3％与35.2±2.9％,68.4±8.2％与80.1±7.3％,68.4±6.3％与55.4±7.0％,两者间均无显著性差别。但10μmol/L硝苯吡啶对α_1受体收缩效应的阻断作用则在SHRSP大鼠大大超过WKY大鼠,最大收缩张力分别降为对照时的3.1±1.5％与56.5±4.8％(P<0.01),9.0±4.1％与23.6±3.5％(P<0.05),5.9±2.5％与28.0±0.8％(P<0.01)。整体动物实验也显示硝苯吡啶的降血压作用及对苯肾上腺素升血压效应的阻断作用在SHRSP大鼠都较WKY大鼠显著增强。离体主动脉a_1受体激动时的快速相与持续相收缩均主要由α_(1B)亚型激动引起,硝苯吡啶对快速相收缩的阻断作用在SHRSP与WKY大鼠无显著性差别,但对持续相收缩的阻断作用则在SHRSP大鼠显著强于WKY大鼠。上述结果提示SHRSP大鼠血管α_1受体两种亚型的分布没有显著改变,但α_(1B)受体激动时继发性细胞外Ca~(2+)进入的途径由非双氢吡啶敏感性钙通道转变为双氢吡啶敏感性钙通道。     

Differential expression of K+ channel mRNAs in the rat brain and down-regulation in the hippocampus following seizures.

K+ channels are major determinants of membrane excitability. Differences in neuronal excitability within the nervous system may arise from differential expression of K+ channel genes, regulated spatially in a cell type-specific manner, or temporally in response to neuronal activity. We have compared the distribution of mRNAs of three K+ channel genes, Kv1.1, Kv1.2, and Kv4.2 in rat brain, and examined activity-dependent changes following treatment with the convulsant drug pentylenetetrazole. Both regional and cell type-specific differences of K+ channel gene expression were found. In addition, seizure activity caused a reduction of Kv1.2 and Kv4.2 mRNAs in the dentate granule cells of the hippocampus, raising the possibility that K+ channel gene regulation may play a role in long-term neuronal plasticity.     

A comparison of chloride, bromide, and sucrose dilution volumes in neonatal pigs

Use of 36Cl, 82Br, and [3H]sucrose to estimate extracellular water volume was evaluated in 14 piglets (7-14 days old). 36Cl and 82Br were distributed in approximately the same volume, but a period of 5-6 hr after injection was required to reach equilibrium in the neonatal pig. Dilution volumes calculated before equilibration (2-5 hr) for 36Cl (326 +/- 11 ml/kg) and 82Br (328 +/- 13 ml/kg) were different from equilibration (6-8 hr) phase volumes (356 +/- 13 ml/kg and 355 +/- 13 ml/kg, respectively; P less than 0.001). A 3-hr sample estimated the same volume distribution calculated by extrapolation of the 6- to 8-hr period because of the relationship between the two slopes of the plasma clearance curves. After the 82Br and 36Cl had achieved equilibration, each was distributed in a volume equivalent to total body chloride space (362 +/- 29 ml/kg) measured by neutron activation; no statistical differences were found (P = 0.6). The early equilibration phase measured a 10% smaller, faster exchangeable fraction of total body Cl. Sucrose dilution volume (332 +/- 19 ml/kg) required multiple plasma samples for extrapolation and measured a dilution volume 7% smaller (P less than 0.05) than total body chloride space.     

青海省角叶蚤属一新种：（蚤目：角叶蚤科）

本文报告青海省贵南县角叶蚤属 Ceratophyllus Curtis,1832 一新种,命名为贵南角叶蚤Ceratophyllus (Ceratophyllus) guinanensis sp.nov.     

大仓鼠肥满度的研究

本文依公式K=100W/L~3计算了大仓鼠肥满度。统计结果表明,雌性肥满度大于雄性肥满度。肥满度随年龄增长而减小。不同作物类型样地中大仓鼠的肥满度变化不明显。不同季节肥满度有一定的变化,主要与繁殖和气候有关。肥满度与种群密度之间不存在明显的对应关系。     

Identification of the nuclear matrix and chromosome scaffold in dinoflagellate Crypthecodinium cohnii~1

Dinoflagellate is one of the primitive eukaryotes,whosenucleus may represent one of the transition stages fromprokaryotic nucleoid to typical eukaryotic nucleus.Usingselective extraction together with embeddment-free sectionand whole mount electron microscopy,a delicate nuclearmatrix filament network was shown,for the first time,indinoflagellate Crypthecodinium cohnii nucleus.Chromosomeresidues are connected with nuclear matrix filaments to forma complete network spreading over the nucleus.Moreover,we demonstrated that the dinoflagellate chromosome retainsa protein scaffold after the depletion of DNA and solubleproteins.This scaffold preserves the characteristic mor-phology of the chromosome.Two dimensional elec-trophoreses indicated that the nuclear matrix and chromo- some scaffold are mainly composed of acidic proteins.Ourresults demonstrated that a framework similar to the nuclearmatrix and chromosome scaffold in mammalian cells appearsin this primitive eukaryote,suggesting that these structuresmay have been originated from the early stages of eukaryoteevolution.     

云南所麻蝇属一新种记述：双翅目：麻蝇科

作者在整理1985年采集的麻蝇科标本中,发现所麻蝇属(SarcosolomoniaBaranov)1新种。模式标本分别保存于云南省卫生防疫站和军事医学科学院微生物流行病研究所。     

长苞铁杉的核型分析及其分类学意义

本文首次分析了特产我国的长苞铁杉亚属(Subgen. Paleotsuga)的代表种长苞铁杉Tsuga longibracteata的核型,它全由中部和近中部着丝粒染色体组成,核型公式为K(2n)=24=22m 2sm,属“lA”类型。第12号染色体具“长着丝点区域”。染色体相对长度组成为2n=12M_2 10M_1 2S。作者发现铁杉亚属(Subgen. Tsuga)植物的核型全为“2A”类型。胞核学资料支持对长苞铁杉亚属和铁杉亚属的划分并表明前者(长苞铁杉)较为原始。长苞铁杉应隶于长苞铁杉亚属、长苞铁杉组。     

人参根系发育形态学的研究

人参(Panax qinseng C. A. Meyer)属于直根系植物,有次生构造。一年生苗只具有主根和侧根。二年以上的人参常在根状茎上长出不定根,即人参根系包括主根和不定根及其各级分枝。主根初生木质部为三原型,侧根和不定根及其分枝多为二原型,偶见三原型。根系随参龄的增加而增大。每年末级分枝自基部于休眠前萎缩、脱落,并在萎缩部分的上一级支根内部产生越冬根原基,越冬根原基是翌年形成全部吸收根的基础。一年生人参由中柱鞘产生一圈初生树脂道,由形成层产生一圈(或二圈)次生树脂道,以后次生树脂道的圈数随参龄的增加而每年增加一圈,自第五年开始渐缓。根内淀粉粒含量随发育时期的变化而相应变化,其积累高峰出现在果后期。研究人参根系发育形态学不仅对全面正确认识人参根系具有理论意义,而且对改进人参栽培管理和评价人参质量具有指导意义。